Midlife Women's Poor Sleep Can Cause Them Cardiovascular Diseases

Poor sleep patterns in midlife can cause a higher risk of Cardiovascular Diseases (CVD) among women. Having ongoing trouble sleeping, especially having short sleep, can increase the risk of heart disease among women aged 40-65 years by 70-75 per cent. This relationship between sleep patterns and cardiovascular diseases among women in their midlife and how a persistent poor pattern of sleep can cause a high risk of CVD was revealed in a study recently published in the American Heart Association’s Circulation Journal. Read on to learn more about this finding. 

The study was conducted over two decades on women in their midlife. Around 50 per cent of women revealed that they struggle with sleep issues in their midlife, while cardiovascular diseases are the topmost cause of death among women. Midlife is a crucial time for women for both heart health and sleep patterns, especially during menopause. During menopause, women are at a higher risk of heart disease.

How was the study conducted?

The study tested whether the trajectories of insomnia or changing sleep duration of women in midlife were related to cardiovascular diseases among participants of SWAN (Study of Women’s Health Across the Nation). The participant women aged 42 to 52 years got their sleep patterns tested 16 times over 22 years.  Beginning in 1996, up to 2,964 participants aged 42 to 52 from different sites in the US participated in the annual examination. These women were premenopausal or early perimenopausal, not using hormone therapy, and free of CVD. In a total of 16 visits, the study used questionnaires to assess insomnia symptoms, typical daily sleep duration, vasomotor symptoms and depressive symptoms. 

The study also indulged in anthropometric measurements; phlebotomy; and CVD event ascertainment. Two types of study models were used- group-based trajectory modelling and the Cox proportional hazard model. The sleep trajectories were measured through the group-based trajectory modelling while the sleep pattern's relation with cardiovascular diseases was measured through the Cox proportional hazard model considering factors like size, age, race, education and CVD risk. 

The results of the study

As a result, four trajectories of insomnia symptoms were discovered among the women. The first was low insomnia affecting 39 per cent of women, the second is moderate insomnia symptoms decreasing over time affecting 19% of women, the third is low insomnia symptoms increasing over time affecting 20 per cent of women, and lastly, high insomnia symptoms that persisted affecting 23 per cent of women. The study revealed that women with persistently high insomnia symptoms had a 1.71 times higher risk of cardiovascular diseases than those with lower symptoms of insomnia. 

Moreover, the sleep duration study revealed four patterns-  persistently short (~5 hours, 15%), moderate (~6 hours, 55%), and moderate to long (~8 hours, 30%). Women with persistent short sleep have a 1.51 times higher risk of cardiovascular diseases. 

Strengths and limitations of the study

The biggest strength of the study is that it was conducted over two decades with 16 appointments which makes it a comprehensive study. Unlike previous studies which stretched over a certain period of time, this study covers the entire midlife giving us insight into the chronic poor sleep patterns's relation with cardiovascular diseases among older women. 

However, the study also has a limitation. The study included moderate to long sleep patterns spanning over 7.70 hours but excluded the sleep that goes beyond this time limit. Moreover, the study considered insomnia and sleep duration but not other factors of sleep like timing and regularity. 

.